﻿//download.js v3.0, by dandavis; 2008-2014. [CCBY2] see http://danml.com/download.html for tests/usage
// v1 landed a FF+Chrome compat way of downloading strings to local un-named files, upgraded to use a hidden frame and optional mime
// v2 added named files via a[download], msSaveBlob, IE (10+) support, and window.URL support for larger+faster saves than dataURLs
// v3 added dataURL and Blob Input, bind-toggle arity, and legacy dataURL fallback was improved with force-download mime and base64 support

// data can be a string, Blob, File, or dataURL




function download(data, strFileName, strMimeType) {

    var self = window, // this script is only for browsers anyway...
		u = "application/octet-stream", // this default mime also triggers iframe downloads
		m = strMimeType || u,
		x = data,
		D = document,
		a = D.createElement("a"),
		z = function (a) { return String(a); },


		B = self.Blob || self.MozBlob || self.WebKitBlob || z,
		BB = self.MSBlobBuilder || self.WebKitBlobBuilder || self.BlobBuilder,
		fn = strFileName || "download",
		blob,
		b,
		ua,
		fr;

    //if(typeof B.bind === 'function' ){ B=B.bind(self); }

    if (String(this) === "true") { //reverse arguments, allowing download.bind(true, "text/xml", "export.xml") to act as a callback
        x = [x, m];
        m = x[0];
        x = x[1];
    }



    //go ahead and download dataURLs right away
    if (String(x).match(/^data\:[\w+\-]+\/[\w+\-]+[,;]/)) {
        return navigator.msSaveBlob ?  // IE10 can't do a[download], only Blobs:
			navigator.msSaveBlob(d2b(x), fn) :
			saver(x); // everyone else can save dataURLs un-processed
    } //end if dataURL passed?

    try {

        blob = x instanceof B ?
			x :
			new B([x], { type: m });
    } catch (y) {
        if (BB) {
            b = new BB();
            b.append([x]);
            blob = b.getBlob(m); // the blob
        }

    }



    function d2b(u) {
        var p = u.split(/[:;,]/),
		t = p[1],
		dec = p[2] == "base64" ? atob : decodeURIComponent,
		bin = dec(p.pop()),
		mx = bin.length,
		i = 0,
		uia = new Uint8Array(mx);

        for (i; i < mx; ++i) uia[i] = bin.charCodeAt(i);

        return new B([uia], { type: t });
    }

    function saver(url, winMode) {


        if ('download' in a) { //html5 A[download] 			
            a.href = url;
            a.setAttribute("download", fn);
            a.innerHTML = "downloading...";
            D.body.appendChild(a);
            setTimeout(function () {
                a.click();
                D.body.removeChild(a);
                if (winMode === true) { setTimeout(function () { self.URL.revokeObjectURL(a.href); }, 250); }
            }, 66);
            return true;
        }

        //do iframe dataURL download (old ch+FF):
        var f = D.createElement("iframe");
        D.body.appendChild(f);
        if (!winMode) { // force a mime that will download:
            url = "data:" + url.replace(/^data:([\w\/\-\+]+)/, u);
        }


        f.src = url;
        setTimeout(function () { D.body.removeChild(f); }, 333);

    } //end saver 


    if (navigator.msSaveBlob) { // IE10+ : (has Blob, but not a[download] or URL)
        return navigator.msSaveBlob(blob, fn);
    }

    if (self.URL) { // simple fast and modern way using Blob and URL:
        saver(self.URL.createObjectURL(blob), true);
    } else {
        // handle non-Blob()+non-URL browsers:
        if (typeof blob === "string" || blob.constructor === z) {
            try {
                return saver("data:" + m + ";base64," + self.btoa(blob));
            } catch (y) {
                return saver("data:" + m + "," + encodeURIComponent(blob));
            }
        }

        // Blob but not URL:
        fr = new FileReader();
        fr.onload = function (e) {
            saver(this.result);
        };
        fr.readAsDataURL(blob);
    }
    return true;
} /* end download() */


